呈现视图 controller 也可以是呈现视图 controller 吗？

Question

On top of an existing view I want to: a) display a screen to the user b) then send an SMS c) display another screen to the user.

For a) I am doing this:

[[UIApplication sharedApplication].delegate.window.rootViewController presentViewController: firstController animated: NO completion:nil];

and for b) I am doing the same thing, except this is presenting a different vc of course, a MFMessageComposeViewController.

However in order for b) to appear I first have to dismiss the first view controller using:

   [[UIApplication sharedApplication].delegate.window.rootViewController dismissViewControllerAnimated:NO completion: nil];

That works so far, I can see the first view appear then see the SMS compose view appear. When the SMS is sent I am doing this to dismiss the SMS compose view

   [[UIApplication sharedApplication].delegate.window.rootViewController dismissViewControllerAnimated:NO completion: nil];

But then nothing happens when I try to present another screen to the user using presentViewController. I can't see any reason why this should be, is there something I'm not aware of?

Actually the screen before the SMS view and after it are the same except they have different text, so the easiest sequence of steps would be:

a) present the view controller with text "abc" b) present the SMS controller c) when the SMS is sent dismiss the SMS controller d) update the text in the first view controller using an IBOutlet e) dismiss the first view controller.

However as mentioned earlier on, if I don't dismiss the first view controller the SMS controller will not appear. So my main question is how can I present the SMS controller on top of the first view controller?

Answer 1

You can either present one after the other closes:

UIViewController *rvc = [UIApplication sharedApplication].delegate.window.rootViewController;
[rvc dismissViewControllerAnimated:NO completion:^{
    [rvc presentViewController: secondController animated: NO completion:nil];
}];

Or present another on top:

UIViewController *rvc = [UIApplication sharedApplication].delegate.window.rootViewController;
UIViewController *pvc = rvc.presentedViewController;  // you may need to loop through presentedViewControllers if you have more than one
[pvc presentViewController: secondController animated: NO completion:nil];

Answer 2

iOS does not allow you to open two modal views at the same time. The modal view is designed to be the topmost view.

Answer 3

In my case, I have access directly to the presented view controller so in that case:

self.present(viewControllerToPresent, animated: true) {
    //It's presented.
}

Answer 4

I just tried it on iOS15. Yes a presented VC can present another VC.

VC1 --> present--> VC2

Answer 5

extension UIViewController{

    /// most top presented view controller
    var presentedTop:UIViewController {
        var ctrl:UIViewController = self;
        while let presented = ctrl.presentedViewController {
            ctrl = presented;
        }
        return ctrl;
    }
}
// call somewhere someCtrl.presentedTop.present(vc, animated:true)